Constructing Rough-Surfaced High-Entropy Spinel Ceramic Nanofibers for Superior Microwave Absorption and Radar Cross-Section Reduction

Designing EMW absorbers that simultaneously achieve high-temperature stability and lightweight features is critical for harsh operating conditions. In this study, we employed electrospinning coupled with calcination to synthesize equimolar (Fe 0.2 Co 0.2 Ni 0.2 Cu 0.2 Mn 0.2 ) 3 O 4 high-entropy ceramic nanofibers (HECNF). Benefiting from the entropy-driven stabilization effect, the five constituent metal elements formed a single-phase spinel solid solution. By tailoring the calcination temperature from 600 to 900 °C, grain growth was induced to construct a unique lightweight porous fiber surface architecture. The high-entropy composition introduces severe lattice distortions and oxygen vacancies. When combined with the unique rough 1D fibrous morphology, these defects trigger a synergistic effect that notably amplifies interfacial polarization. Consequently, the as-prepared nanofibers exhibit superior microwave absorption performance, achieving a minimum reflection loss (RL min ) of -46.20 dB and an effective absorption bandwidth (EAB) of 5.14 GHz. Furthermore, CST simulations were conducted to verify that the material can significantly reduce the radar cross section (RCS) under practical conditions. This work provides a novel strategy for designing high-performance EMW absorbing materials for harsh environments via the synergistic regulation of micromorphology and high-entropy composition.